I have seen this trend with a few of the sites I manage and am wondering what the correlation is. If you have seen a similar trend my speculation is that it is one of two things:
1) Your website is mobile optimized and users are able to quickly get the information they need and then leave the site.
2) Your website is not mobile optimized and users get frustrated waiting for the site to load and the content to format and leave the site to find the info elsewhere.
Just looking at some of the clients I manage, on average traffic from mobile search has gone up over 130% in the last six months, with around 35% of traffic coming from mobile. This tells me it is critical your website be mobile optimized.
Often times, mobile users are searching your site to get operational information, such as location, directions, telephone number and business hours. If your site is not mobile optimized I would recommend that at minimum, you have the following information on your home page:
1) Business hours
2) Business locations with a link to Google maps
3) Business phone number
4) Parking information if applicable
5) Email address if you accept emails from customers
Display it prominently, either in the header or footer or sidebar where it can be easily seen, and make sure phone numbers and links are mobile optimized so visitor can just click to dial the number.
Best is to have a fully mobile optimized or mobile responsive website. If you need help, I can help you with this and get you on the right direction.
There is no denying mobile information is increasingly a part of our everyday world. Make it easy for the customers and prospect to do business with you, no mater how they are trying to reach you, in person, phone, online via desktop or mobile.